1. Technical Field
The invention relates to a device for fixing soft tissue, and more particularly to a device for affixing glenoidal labrum to a shoulder joint.
2. Related Art
A shoulder joint is mainly composed of a ball-like humeral head and a glenoidal cup of scapula, tightly covered by various fibered connective tissues and muscles, performing flexion, extension, adduction, abduction, rotation and circumduction. Moreover, a glenoidal labrum is formed on the edge of the glenoidal cup of the shoulder joint, increasing the surface area of the glenoidal cup, enhancing stability of the shoulder joint, and providing attachment for ligaments.
Operating frequently, the shoulder joint is easily injured or dislocated. Soft tissue, such as ligaments, tendons and cartilage, of the shoulder joint is easily separated therefrom due to sport injury, overuse, or improper posture. Injury to the shoulder joint often includes tearing of tendons of rotator cuff muscles, SLAP (Superior Lesion, Anterior to Posterior, wherein the upper part of the glenoidal labrum is pulled off the glenoidal cup by tendons of biceps of humerus), and Bankart lesion (the lower part of the glenoidal labrum is separated from the glenoidal cup by dislocation of the humerus and drag of the ligament).
The soft tissue of the shoulder joint requires surgical intervention when seriously separated therefrom, such intervention comprising open and arthroscopic techniques. In both cases, suturing directly or indirectly secures the torn or separated soft tissue to the bones of the shoulder joint. For example, torn rotator cuff tendons are attached to the humerus or separated glenoidal labrum to glenoidal cup of the shoulder joint by such suturing.
In a direct fixation method, the soft tissue is directly sutured to bones with drilled holes. Specifically, the soft tissue is fixed to the bones by seaming the sutures between the soft tissue and the holes. This direct fixation method, however, is very time consuming and requires a high degree of surgical precision. Moreover, the sutures are easily broken, adversely affecting reconstruction and regeneration of the soft tissue.
In an indirect fixation method, the soft tissue is fixed to bones by soft tissue anchors. Specifically, the soft tissue anchors are disposed in the bones and the soft tissue is then fixed to both the soft tissue anchors and bones by sutures. There are two types of conventional soft tissue anchor, push-in and turn-in. The push-in soft tissue anchor may comprise ridges, barbs, or extending wings or fingers. When employed, the push-in anchor is inserted into the bones and the ridges, barbs, or extending wings or fingers thereof engage the bones, as disclosed as a suture anchor with annular ridges in U.S. Pat. No. 5,100,417, a harpoon suture anchor with barbs in U.S. Pat. No. 5,141,520, an umbrella-shaped suture anchor device with outwardly extending wing members in U.S. Pat. No. 5,545,180, and a knotless suture anchor with extended fingers in U.S. Pat. No. 6,692,516. The turn-in soft tissue anchor may comprise a tip and threads. When employed, the tip and threads thereof are inserted into the bones, as disclosed in U.S. Pat. No. 4,632,100, U.S. Pat. No. 5,156,616, U.S. Pat. No. 5,851,219, and U.S. Pat. No. 6,117,162.
Accordingly, conventional soft tissue anchors require sutures to pass through eyelets or apertures thereof and to be knotted to secure the soft tissue to bones, complicating surgery. Moreover, when conventional soft tissue anchors are employed in arthroscopic surgery, such for fixing SLAP, operation thereof is very difficult due to limited space. Thus, attaching the separated glenoidal labrum to the glenoidal cup of the shoulder joint by the conventional soft tissue anchors is difficult and time-consuming.